When he's not showing his butt on national TV, popular One Direction star Niall Horan, 19, may have hoped to show it to Big Brother's famously excitable Hazel O'Sullivan, 24, according to reports by the Daily Star.

The Irish One Directioner reportedly fell for her at first sight when he spotted the busty Irish model at a party.

'He really tried it on. He thought he had a chance,' a source reportedly told the UK newspaper.

However, O'Sullivan was apparently oblivious to Niall's worldwide fame and impressive bank balance.

'My initial reaction when I saw him was 'How did this lad get into the party?' because he looked so young,' Hazel said.

She was left 'shocked' when she discovered it was Harry Styles' mate who was pursuing her and confessed 'he was the one that got away.'

Next time she may want to read the entertainment rags to figure out who's who.